How to stop caring about someone?

I broke up with this girl (in fact she dumped me as a huge sack of garbage) like five months ago. I haven't got a real girlfriend since then but I have had some kind of activity with some random girls (if you know what I mean). I'm not actively looking for dating right now as I am involved in some other issues concerning my career. There is one thing that truly annoys me and it is that I think I still care about my last girlfriend. Don't get me wrong, it is not like I am craving to be with her again, in fact it would be nice to not see her anymore at all (last time I saw her was like two months ago). I really want to stop caring about her, she doesn't deserve the attention my brain is giving towards her memories in my mind. I am not in her social-network network anymore, as we are no longer connected by Facebook, whatsapp, Skype, twitter, you name it, so it is easier now to not have any remaining artificial attachment to her, but every now and then my brain play me fool. Any advices, I think I would be "cured" as far as I start seriously dating again, but right now that is not a viable option. Thanks!